With the official opening of the new River Oaks District mixed-used complex less than six weeks away, the luxury center is putting together the final pieces of its retail puzzle. It's landed another interesting new store, as COS, the upscale, more sophisticated sister brand of fast fashion giant H&M is headed to the complex on Westheimer near the 610 Loop.

COS, short for Collection of Style, was launched in 2007 in London, offering classic clothing, featuring leather, suede, fine fabrics and cashmere, at affordable prices, with many items under $100. It has attracted celebrity fans like Kate Bosworth and Olivia Palermo.

It will be the first COS store in Texas, joining locations in New York and Los Angeles that opened last year with additional stores planned for New York, Boston and southern California in the coming months. The 4,380-square-foot Houston store, which is expected to follow the design features of natural materials and minimal features at other COS boutiques, will be the largest U.S. store thus far and will offer both women's and men's clothing and accessories.

"With COS expanding to the U.S. only last year, we are excited to introduce the quickly growing brand to River Oaks District shoppers," said Jeff Zeigler, senior managing director of retail services for OliverMcMillan, which is developing the center.

River Oaks District officially opens October 1, although Cartier plans to occupy its new space on September 3. Other tenants include Dior, Hermès, Intermix, Stella McCartney, Tom Ford, Dolce & Gabbana, Roberto Cavalli, Moncler, Chopard and Van Cleef & Arpels, along with an iPix theater and Equinox gym.